Esters of oxypropylated derivatives of substituted phenol sulfonic acid salts, and method of making same



United States Patent "ice ESTERS OF OXYPROPYLATED DERIVATIVES OF SUBSTITUTED PHENOL SULFONIC ACID SALTS, AND IVIETHOD OF MAKING SAME Melvin De Groote, University City, Mo., assignor to Petrolite Corporation, a corporation of Delaware No Drawing. Application May 27, 1950, Serial No. 164,859

6 Claims. (Cl. 260-402) The present invention is concerned with esters of oxypropylated derivatives of certain substituted phenolsulfonic acid salts and the method of making same. For many purposes the sodium salt is suitable and most economical to prepare. However, as far as the sulfonic acid is concerned, it may be in combination with various cations, as hereinafter described. For the sake of simplicity, the invention will be described primarily from the standpoint of a sodium or potassium salt, particularly the former. The acid radical of the ester is supplied by a detergent-forming monocarboxy acid having at least 8 and not more than 56 carbon atoms. The higher fatty acids having 8 to 18 carbon atoms are particularly desirable as a source of the acyl radical.

In my co-pending application Serial No. 164,857 filed May 27, 1950, I have described a sulfonic acid salt of the following structure:

g S03.Na

in which the occurrences of R have their previous significance, shall be insoluble in a mixture of two-thirds non-aromatic kerosene and one-third xylene; and the corresponding sodium salt R SOs.Na

in which the occurrences of R and n have their previous significance and n has the identical value, as previously, shall be soluble in a mixture consisting of two-thirds nonaromatic kerosene and one-third xylene.

In many instances, and in fact, in nearly all instances, the hydrophobe character of the compound of the kind just specified is not sufiicient to give solubility in nonaromatic kerosene alone. However, when esterified with a higher fatty acid or the equivalent, as previously noted, the resultant ester is usually, and almost without exception, kerosene-soluble. Such new compounds, completely soluble in non-aromatic kerosene, are particularly val- 2,716,127 Psi-tented Au 23, 1955 uable as coupling agents and for other purposes such as an additive for lubricating oils, particularly petroleum lubricating oils, to give added detersive qualities, and hence, other desirable characteristics.

More specifically then, the instant invention, as pointed out in the claims, is concerned with an ester salt of the following formula:

S O acation in which R is selected from the class of hydrocarbon substitutents and hydrogen atoms, with the proviso that there must be at least one hydrocarbon substituent and that the total number of carbon atoms substituted in the phenolic ring he not less than 12 and not over 35, and with the proviso that n be not less than 10 and not more than 50; in which RCO is the acyl radical of a monocarboxy detergent-forming acid having at least 8 and not over 56 carbon atoms; and with the proviso that the corresponding sodium salt SOzsodiurn in which the occurrences of R, R and n have their previous significance and n has the identical value as previously, shall be soluble in non-aromatic kerosene; and with the further proviso that the corresponding unacylated sodium salt SO3.N3,

in which the occurrence of R and n have their previous significance and n has the identical value as previously, shall be insoluble in non-aromatic kerosene.

In order to permit convenient comparison with my aforementioned co-pending application Serial No. 164,857 filed May 27, 1950, the present applicationis divided into two parts:

Part 1 is concerned with the preparation of the oxypropylated derivatives of substituted phenolic sulfonic acids and the method of making same; and

Part 2 is concerned with the esters derived therefrom and the particular method of preparing the esters. For all practical purposes part 1 is in essence a verbatim reproduction of the text of my aforementioned co-pending application Serial No. 164,857, filed May 27, 1950.

PART 1 Regardless of what the cation happens to be, however, the sulfonic acid, prior to oxypropylation, must be characterized by the fact that the sodium salt is xylenesoluble; After oxypropylation, but before esterification, the hydrophobe character is increased and the product is still soluble in xylene, but also soluble in mixtures of xylene and kerosene or kerosene having substantial aromatic character. The initial salt does not have this characteristic.

In an important and restricted sense, the present invention is concerned with a two-step procedure:

(a) Treating a water-soluble xylene-soluble sodium eeaaeaaaaea salt of a substituted phenol-sulfonic acid withpropylene make the resulting compound or compounds even more soluble in xylene; or, better still, soluble in axylenekerosene mixture, or in a kerosene of substantial aromatic character; and

(b) Esterifying such alcohol salts in the sense that there are both a salt structure and an esterifiable alcohol radical present, with a detergent-forming monocarooxy acid of the kind described.

Such esterified alcohol salts, and particularly the esterified alcohol salt, when sodium contributes the cation, and higher fatty acids contribute the acid radical, are valuable as additives in theiprepiaration of emulsions. Extremely dilute emulsions, for instance, those in which the dispersed phase is less than two-tenths of a per cent, and usually less than one-tenth of a per cent, have been prepared without using an emulsifying agent. The majority of emulsions, however, are prepared by the use of an emulsifying agent, and thus, the emulsion system consists-essentially of three ingredients. However, many technical emulsions actually have a fourth ingre dient, which may be an emulsifier of indifferent or inferior effect, but is valuable, because it is a coupling agent or mutualsolvent. See The Composition & Structure of Technical Emulsions, J. H. Goodey, Royal Australian Chem. Inst, J. & Proc., 16, 1949, pp. 47-75.

There are available a large number of phenols which can be converted into sulfonic acids, into the oxypropylated derivative, then into the ester, and then into the corresponding sodium salt. 'As previously indicated, the particular sulphonate selectedas the starting material for the present purpose, is one which is water-soluble and also xylene-soluble, in the form of the sodium salt.

Phenols of utility for the present use, include those in which the substituted radical, frequently an alkyl radical, has 12 or more. carbon atoms; in fact, sometimes as many as 35 carbon atoms. The substituent group n eed not be a straight or branched chain, but may be a'cyclicgroup or a combination of a cyclic group and a long chain group, such as an alkylaryl group, or a hydrogenated alkylaryl group.

Suitable methods for preparing sulfonates of the kind employed as starting materials in the present invention have been described in a number of patents, including the following:

Patent No. Patent No.

2,133,287, dated Oct. 18, 1938, to Flett 2,134,711, dated NOV. 1,1938, to Flett Patent-No. 2,134,712, dated Nov. 1, 1938, to.Flett Patent No. 2,166,136, dated July 18, 1939, to Flett Patent No. 2,186,132, dated Jan. 9. 1940, to Zink Patent No. 2,205,947, dated June 25, 1940, to Flett Patent No. 2,205,948, dated June25, 1940, to Flett Patent No. 2,223,363, dated Dec. 3, 1940, to-Flett Patent No. 2,256,610, dated Sept. 23,1941, to Buc Patent No. 2,249,757, dated July 22, 1941, to Flett Patent No. 2,283,199, dated May 19, 1942, to Flett 1' Particular reference is made to U. S. Patent No. 2,205,948, which describes a mixture of a plurality of ,alkylphenol sulfonates, which, in the form of the free sulfonic acids, correspond with the formula:

RCH2 I 30311 inlwhich R represents an alkyl hydrocarbon radical con- 'taining ll to 22 carbon atoms, the alkyl radicals reprereadily susceptible to alkylation, particularly in the case where one introduces a higher alkyl radical. Seeaforernentioned U. s. Patent No. 2,223,363, which describes an alkyl derivative of a hydroxydiphenyl sulfonate, of

4 which the alkyl group is derived from a hydrocarbon of a petroleum distillate containing 7 to 35 carbon atoms.

My preferred sulfonates are those described under the headings of Examples 4, 5 and 6 in the aforementioned 5 U. S. Patent No. 2,166,136, and Example 1 of aforementioned Patent No. 2,223,363.

Another suitable procedure is toproduce polyalkylated diphenyl compounds in the manner described in U. S. Patent No. 2,135,978, dated November 8, 1938, to

l" Magoun, but moderate the sulfonation so as to produce examined to see if it is water-soluble, so as to give a 1% to 5% solution in water at ordinary temperature, approximately to C. It is then examined for xylene solubility and should show approximately the same solubility in xylene, under the same conditions, although such solubility may be slightly less, for instance,

as little as /2%. The product is then subjected to oxypropylation, using an amount of propylene oxide atlleast equal to one-third mole of propylene oxide for each carbon atom present in the phenyl sulfonate. If this 5 amount of propylene oxide does not give distinct reduction in the hydrophile property and increase the solubility in the xylene-non-aromatic kerosene mixture such as 75% xylene-25% kerosene,.to a 65% kerosene and xylene mixture, the process is continued until the 1 amount of propylene oxide. added in molar amount, is twice the number of carbon atoms, present in the phenol sulfc mate. If, at this stage, the resultantproduct does not show significant and marked decreasein hydrophile property and increased hydrophobe property bya Reid- 5 sene test or kerosene-xylenemixture test, the product is discarded as not being suitable.

In light of the variety of phenol sulfonates that may be employed, it is obvious that, in ,a general way, as the number of carbon atoms in the substituent group or groupsgo up, less propylene oxide willbe required, everything considered, to yield xylene solubility. This means that in the rule sug'g'estedpreviously, the lower amount of propylene oxide is apt to be used in connection with the sulfonates of the higher or highest molecular weights,

i. e. largest number of carbon atoms in the substituent group .or groups. ,Thefact that further generalization is not helpful, is, for obvious reasons, to wit, the'fact that the substituent may be, as noted, straight chain or branched, cyclic or non-cycli'c, or both types may be present. Similarly, reference has been made to the use of the oxypropylated derivatives'in lubricating oils. This applies to both synthetic lubricating oils obtained by polymerization of alkylene oxides and lubricating oils obtained from the usual petroleum sources. Insofar that his only required that the product, or products, show decreased hydrophile properties and solubility inn-kerosene-xylene mixture, but not necessarily in kerosene alone, this statement may be, something of an incongruity. Actually, however, even though oxypropylation products do not show complete kerosene solubility, particularly in non-aromatic kerosene, yettheyrcan be added to the synthetic polyoxyalkylene lubricants and also to the con- 7 ventional lubricants, due to the presence of various polar andsemi-polar additives which are customarily added.

' ,l There are available a number of petroleum distillates which are in the same distillation range as kerosene, but ,due to their aromatic character, are notentirely satisifactory, in .some instances, for purposes for which keroseneis used. Suchmaterials are sometimes referred to ,,as,kerosene range distillates, or kerosene-range solvents.

:lnsofarhthat much kerosenegordinarily produced is used for.,a' solvent, rather than for combustion orillum'ina'tion, differentiation is made inthe present description, for

' Summarizing what'has' be en said, thep'reS'ntinvention is concerned with a sulfonic acid salt of the following structure:

30 .Oat' R 3 10121 in which R is selected fromthe class of hydrocarbon substituents and hydrogen atoms, with the proviso that there must be at least one hydrocarbon substituent and that the total number of carbon atoms substituted in the phenolic ring be not less than 12 and not over 35, and with the proviso that n be not less than 10 and not more than 50; and with the further proviso that the corresponding sodium salt 3 some in which the occurrences of R have their previous significance, shall be xylene-soluble and the corresponding sodium salt SOa.Na

into a compound soluble in the previously described xylene-non-aromatic kerosene mixturev and of the following structure:

(CQ aCDHH g S0a.Na

in which R is selected from the class of hydrocarbon substituents and hydrogen atoms, with the proviso that there must be at least one hydrocarbon substituent and that the total number of carbon atoms substituted in the phenolic ring he not less than 12' and not over 35, and with the proviso that n be not less than and not more than 50.

Needless to say, potassium salts would serveas satisfactorily as sodium salts, and in essence, in the broadest aspect, the invention is concerned with a cation attached to the S03 radical being either sodium or potassium, or other cations, as subsequently noted.

As far as the ultimate product goes, the same compound could be prepared by the sulfonation of an oxypropylated derivative of the following structure:

My preference is to obtain the desired compound by the use of the sodium salt, all else being equal.

The oxypropylation of the sodium sulfonates can be conducted by various procedures. My preference is to prepare a solution or slurry of thefinely-powdered sulfor. mate and xylene, add an alkaline catalyst to the extent of about /z% to 3%, by weight, of the sulfonate, and then proceed with the oxypropylation in absence of water. Oxypropylations are sometimes conducted in the presence of small amounts of water. The alkaline catalyst employed may be any one of the customary catalysts, such as sodium methylate, caustic soda, caustic-potash, etc. Other catalysts can be used in oxypropylation, see Iour: nal of American Chemical Society, volume 68, page 680 Note that reference has been made in the preceding paragraph to a solution or slurry in xylene of the finelypowdered sulfonate. The sulfonates employed herein are xylene-soluble. This is particularly true of solutions containing 5% to 25% or even more, of the sulfonate. In many instances, considerable agitation or heating is necessary to provide a solution in xylene. Therefore, in the initial oxypropylation stage where the amount of xylene is substantially equal in weight to that of the sulfonate, it may not all dissolve, or may not dissolve cold. Thus, reference is made to a solution or slurry. It is pointed out subsequently that one may prefer to use another solvent, for instance, a mixture of two parts of non-aromatic kerosene and one part of xylene. The initial product is not soluble in such mixture, and therefore, the use of the word slurry seems more appropriate.

Oxypropylation may be conducted intermittently or continuously until the appropriate point is reached. Intermittent oxypropylation is particularly valuable for exploratory purposes, such as a routine test to determine the approximate degree of oxypropylation required to convert a xylene-insoluble sulfonate of the kind herein specified, into a xylene-soluble sulfonate. Equipment suitable for continuous oxypropylation obviously may be employed in intermediate oxypropylation.

In the particular procedure employed for preparation of the oxypropylated derivatives herein described, the autoclave was of conventional design. It was made of stainless steel and had a capacity of approximately one gallon and a working pressure of 1,000 pounds gauge pressure. The autoclave was equipped with the conventional devices and openings, such as the Variable stirrer operating at speeds from 50 R. P. M. to 500 R. P. M., the thermometer well and thermocouple for mechanical thermometer; emptying outlet; pressure gauge; manual vent line; charge hole for initial reactants; at least one connection for conducting the incoming alkylene oxide, such as the ethylene oxide, to the bottom of the autoclave; along with suitable devices for both cooling and heating the autoclave, such as a cooling jacket, and preferably, coils in addition thereto, with the jacket so arranged that it is suitable for heating with steam or cooling with water, and further equipped with electrical heating devices. Such autoclaves are, of course, in essence, small scale replicas of the usual conventional autoclave used in oxyalkylation procedures.

Continuous operation, or substantially continuous operation, is achieved by the use of a separate container to hold the alkylene oxide being employed, such as propylene oxide in the instant procedure. The container consists essentially of a laboratory bomb having a capacity of about one-half gallon, or somewhat in excess thereof. This bomb Was equipped, also, with an inlet for charging, and an outlet tube going to the bottom of the container, so as to permit discharging of alkylene oxide in' the liquid phase to the autoclave. Other conventional'equipment consists, of course, of the rupture disc, pressure gauge, sight feed glass, thermometer connection for nitrogen for pressuring bomb, etc. The bomb was placed mediate land continuous oxypropylations, for the reason "that intermediate or batch-wise oxypropylation is a fenie'nt procedure, by Whiphexploratory oxypropylations can be made soas todetermine the initial point where the desired change in solubility has been ob- Solubility in "a xylene-kerosene mixture, of course, re arms as I further dxypropylation proceeds and solubility and hydrophobe characeteristics may increase the degt'eejthat'the product is soluble in a solvent, such whatsoever.

Example v Grams Phenol monosulfonate sodium salt produced in the manner described in Example of aforementioned .U. S. Patent No. 2,166,136--. 300 Xylene 300 Sodium methylate a ,6 Propylene 'oxide 300 Thepowdered sulfonate was-placed in an autoclave with 300 grams of xylene and 6 grams of sodium methylate, as indicated. The'autocla've was then swept out with ""trog e'n 'and sealed. Stirring was started and then heat applied The "temperature was allowed to rise to approximately 175 C. At this point propylene oxide was added'to the extent of'-300' grams. Notwithstanding the "pr csenceof the free hydroxyl radical, oxypropylation to place ra'therslowly. The time required to'combine'the pr'opylene oxide was 3% hours. At no time did the temperature' go above theinitial'temperature of 175 C. 'Like'wise,'the temperature did not drop much blow170" C. at anytime. The maximum operating pressure"was l70 p'ounds" per square inch. The product attHisstageQon'a xylene-free"basisfcalculated as follows: i

7 Per cent lfonate 50.0 Propylene oxide 50.0

On"a"xylene-'containing basis it calculated as follows:

Per cent ulfo'rrate 5 33.3 "P rppylene "oxide"; 33.3

Xylene 33.4 7,

An examination offthis product, both on a xylene-containing basis and after evaporation of xylene, did not sh wa y marked. c an asqlr i y although a ?solubility apparently was decreased to at least some degree.

' I Example 2 The reactidnjiii assabove indicated, except for the llf'arnount of sample withdrawn, was subjected to I "Without the addition of more catalyst, a second '1 gram portion of propyleneoxide was added. The "reaction: timewas flon'ger than before, being- 5 hours. "This rcac'tion t'ook place under substantially the same 8 9C; to' 178: C., andmaxiniurn pressure of 182 pounds square inch. The composition, on a xylene-free basis, was as follows:

isi rt ie 33 3 ing examples there are illustrated both i "is a stra'i'ght run "kerosene having no aromatic character herl oxypropyla'tion"in the manner previously indi 6 conditionsf as previously, i. e., temperature range ofxylene and 35% non-aromatic kerosene.

8 On a xylene-containing basis, it was calculated as follows:

Per cent Sulfonate l;- 25 Xylene 25 Propylene oxide A third portion of propylene oxide (300 grams) was added as before, after the autoclave had been opened and 7 grams of sodium methylate added. After the addition of methylate the autoclave was swept out with nitrogen gas as before; otherwise, the procedure, as far as temperature and pressure were concerned, was the same as in Examples 1 and 2, preceding, i. e., the temperature range was 'within'the limit of 167 C. to 180 C., and the pressure varied from 170 to 187 pounds per square inch. The time required was less than previously, apparently due to the addition of sodiufn methylate, and was 2 /2 hours. At the end ofthis timea'sample showed a continued change in solubility character, i. e., it seemed to be even less water-soluble or -dispersible than before, but was soluble in a mixture of 50% xylene and 50% nonaromatic kerosene. The product itself, on a xylene-free basis, represented 25% Sulfonate and 75 propylene oxide. On a xylene-containing basis it represented 20% sulfonate, 20% xylene and 50% propylene oxide.

Example 4 A final and last addition of propylene oxide was made to the above reaction mass. The amount added was 300 grams. No more catalyst was added. The temperature and pressure ranges were within the same limits, as in Example 3, preceding. The time required, however, was somewhat longer, i. e., 3% h0urs. The product, 'on a xylene-free basis, was water-dispersible and did not show much difference in this property compared with the previous sample. However, itw'as soluble in a mixture of parts of non-aromatic kerosene and 35 parts of xylene and practically dissolved in a mixture of non-aromatic kerosene and 25% xylene. The product, when free from xylene, was a thick, viscous, amber-colored liquid.

Calculated on a xylene-free basis, the product represented 20% Sulfonate and propylene oxide. On a xylene-containing basis, it represented 16.6% sulfonate, 66.8% propylene oxide, and 16.6% xylene.

In the above calculation andin previous calculations,

" no cognizance was taken of the presence of sodium methylate, except as far as weight percentages were conce'r'ned, and no cognizance was taken of the fact that 'small'sarnples of 2 or 3 grams were taken out at the end of intermediate oxypropylations for examination.

Needless to say, this product dissolved in xylene and other comparable organic solvents.

particularly valuable coupling agent in the preparation of emulsions where the emulsifying agent was the original sulfonate itself. It was soluble to the extent of 1% or] 2%, and probably to a greater degree in some typical lubricating oils which contained approximately 10% to 15% of additives. The bulk of these additives "werealkaline earth soaps, mahogany sulfonates, or similar materials. 7

Example 5 Grams Sulfonate as described in Example 1 300 Xylene 300 Sodium methylate 10 Propylene oxide 1200 It proved to be a;

Example 6 Grams Sulfonate as described in Example 4 of aforementioned U. S. Patent No. 2,166,136 300 Xylene 300 Sodium methylate 10 Propylene oxide 1200 The procedure followed was the same as that described in Example 5, preceding, and the solubility characteristics of the final product were substantially the same as in the preceding example.

Example 7 Grams Sulfonate as described in Example 6 of aforementioned U. S. Patent No. 2,166,136 300 Xylene 200 Sodium methylate l Propylene oxide 1200 The procedure followed was the same as that described in Example 5, preceding, and the solubility characteristics of the final product were substantially the same as in the preceding example.

Example 8 Grams Sulfonate as described in Example 1 of aforementioned U. S. Patent No. 2,223,363 300 Xylene 300 Sodium methylate 10 Propylene oxide 1200 The procedure followed was the same as that described in Example 5, preceding, and the solubility characteristics of the final product were substantially the same as in the preceding example.

Example 9 Grams Mono-sulfonated product prepared in the manner described in the first example of U. S. Patent No. 2,135,978, employing 400 parts of fuming sulfuric acid sulfur trioxide) instead of 880 parts of fuming sulfuric acid (21% sulfur trioxide) so as to yield a monosulfonate instead of a polysulfonate 300 Xylene 300 Sodium methylate l0 Propylene oxide 1200 The procedure followed was the same as that described in Example 5, preceding, and the solubility characteristics of the final product were substantially the same as in the preceding example.

The product above described is essentially a polybutylated phenyl phenol monosulfonic acid sodium salt. Equally satisfactory are polyamylated phenyl phenol monosulfonic acid sodium salt, or polyhexylated phenyl phenol monosulfonic acid sodium salt. Similarly, one may employ a polyoctylated phenyl phenol monosulfonic acid sodium salt, or the polydecylated phenyl phenol monosulfonic acid sodium salt.

Referring to the examples obtained by the alkylation of phenol with a kerosene fraction or higher boiling fraction in the manner described in previous examples, and particularly by reference to U. S. Patent No. 2,166,136. It is to be noted that these particular phenol sulfonates are sometimes referred to as keryl phenol monosulfonic 10 acids and the salts, for example, the sodium salt, are referred to askeryl phenol monosulfonic'acid sodium salt. In my preferred examples the keryl radical contains about 13 carbon atoms or 15 carbon atoms, or 17 carbon atoms.

The use of a solvent, particularly xylene, has the. advantage that it can be removed readily by vacuum distillation or other suitable means, as pointed out subsequently, when certain cations other than sodium or potassium iron .appear, it may require the acidification of the sodium salt on a solvent-free basis. If this procedure is to be employed, then and in that event, xylene is preferred as the solvent. However, it is more convenient, instead of using xylene as a solvent, to replace the 300 grams of xylene specified in the various examples, by grams of xylene and 200 grams of non-aromatic kerosene. The use of such solvent has the advantage of practically indicating the end point or at least the initial end point, i. e., degree of oxypropylation, where the product is soluble in a mixed solvent. If batch-wise oxypropylation is being employed, or if continuous oxypropylation is being used and one takes samples intermittently, mere casual examination indicates when the solvent-containing mixture is homogeneous, and usually, this applies for a more dilute sample. In other words, the finished product can be diluted further than with the mixed xylene-kerosene solvent so as to contain 5% or less of the oxypropylation product. When such point is reached, at least the stage of initial solubility in the mixed solvent has been determined. Sometimes samples exhibit solubility in a mixed solvent in concentrated solutions, but require further oxypropylation to make them soluble in dilute solutions, for instance, 2% to 5 of the oxypropylated derivative.

.As has been pointed out previously, the potassium salts can be used as well as the sodium salts, but have no particular advantage, except perhaps somewhat greater solubility in xylene and non-polar hydrocarbon solvents.

Actually, having obtained the sodium salt, or, for that matter, the potassium salt, one can readily prepare other salts which might not necessarily be satisfactory for oxypropylation, in that the cation contains a group susceptible to oxypropylation, as is the case in cyclohexylamine, monoethanolamine, diethanoline, triethanoline, morpholine, and high molal amines, as, for example, the amines 0 (CaHaO),.H

R SO3.H

Such materials which are thrown out by hydrochloric acid can be purified in the conventional manner by evaporation, so as to eliminate the inorganic impurities and the acid, and can then be neutralized with any convenient base, such as those above enumerated, or with ammonia, tertiary amines, or can be converted into the salts of other metals, such as lithium, calcium, magnesium, strontium, barium, etc. The ammonia and amine salts, particularly when derived from water-soluble amines, have utility as coupling agents in the same manner as previously described. In fact, the salts derived from triethanolamine have unusual value as coupling agents. Those derived from high molal amines show increased oilsolubility over and above the sodium salt, as in the case of the cyclohexylamine salt. These salts are particularly valuable lubricant additives. The copper salt is a valuable additive for materials employed to prevent or repel certain types of insect or micro-organic ravage.

-In obtaining 'the free :acid from the sodium s'alt or a p'otas'sium salt, if :it happened -to be employed, it is usually desirable to eliminate the xylene prior to acidification. In some instances, the higher oxypropylated derivatives seem to be slightly heavi'er than water and may separate at the bottom'instead= ofrisin'g to the top. In some instances, this is iptfrely a'question of-how much acid is added. In'other -words,-ifthespecific gravity .of theaqueoushydrochloricacid s'olutio'nis sufliciently high, the product separates at the t'opyotherwis'e, itmay'separate atthe bottom. Sincethefr'e'e acid is xylene-soluble, if xylene or someother solvent is i'present, then and in that event, of course, it affects the specific gravity of the non-aqueous phase, andthus again may'bea factor in determining whether a sup'ernatant layer comes 'out at the'top, or 'an'oily'layer separates at the bottom. The objection to the use of a salt is that at least partial ne'utralizationofthesulfonicacid may take place. less to say, if one intended to prepare the ammonium salt, ammonium chloride =could'be used to hasten the separation. Similarly, if the triethanolamine salt is to be formed, triethanolaminehydrochloride (triethanol ammonium chloride) could be employed.

Reference is now made to a number of previous formulae, in which the divalent radical '-(C3H60')-7L appears. One example is Actually, when such 'products are obtained in the manner herein described, one does not obtain a single derivative, in which n has one and only one value, for instance, '14 or or 16, 'or the like. Actually, one obtains a cogeneric mixture of closely related or touching liomolog'ues. These materials invariably have high molecular weights and cannot be separated from one anotherby any known procedure without decomposition. Th'eproperties of 'such mixture represent the contribution of the various'individual members of the mixture. 011 a s'tati'sticalbasis, of 'course, it can be appropriately specified. For practical purposes, one need only consider the oxypropyla'tion of a monohydric alcohol, because, in essence, this is substantially the mechanism involved. Even in such instances where one is concerned with a 'monohydric reactant, one cannot draw a single formula and say thatbyfollowing such and'such proce'dure,"on'e can readily obtain 80% or 90% or 100% of such com- Howevenin the case of 'at'least monohydric pound. initiahreactants, one can'readily draw the formulae of a large number of compounds which appear in some of the probable mixtures, or can be prepared as components and mixtures which are manufactured conventionally.

Simply by way of illustrationfreference is made to the co-pending application of De Groote, Wirtel and Petting-ill, Serial -No. 109,791, filed August 11, 1949.

However, momentarily referring again to a monohydric initial reactant, itis obvious that if one selects any such simple hydroxylated compound and subjects such compound to oxyalkylation, such as oxye'thylation, or

'oxypr'opylation, it becomes obvious that one 'is really producing a polymer of the alkylene oxide, except for the terminal group. 'Thisis particularly true Where the amount of oxide added is comparatively large, for instance,'10, 20, 30, 40, or 50 units. If such a compound issubjected to oxyethylation, so as to introduce units of ethylene oxide, it is well known that one does not obtain a single constituent, which, for the sake of convenience may be indicated as RO( C2H4O)3OH. Instead, one obtains a' cogeneric mixture of closely related homologues,inwhich the formula maybe shown as the following: "=RO(C2H40)nH, wherein 'n, as far "as "the statistical average goes, is30, but'the individual members Needpresent in significant amount :may vary from instances where n has .a value of 25, and perhapslessyto va.point where '11 may represent 35 iorzmore. :Suchmixture is, as stated, a cogeneric closely .=related series .of touching homologous compounds. Considerable iinvestigation has beenmadein regardito the distribution .curves for linear polymers. Attention .is directed to :the article :entitled Fundamental .Principles of Condensation Polymerization, by Paul J. Flory, whichzappeared'in ChemicaliReviews, volume 39, No. l,. page 137.

Unfortunately, as has been pointed out by Flory and other investigators, there is no satisfactory method, based on either experimental or mathematical examination, of indicating the exact proportion of the various members of touching homologous series which appear' in cogeneric condensation products of the kind described. ,'This means that from the practical standpoint, i. e., the ability to describe how to make the product under consideration and how to repeat such production time -*after:time'without difficulty, it is necessary to resort-to some-other method of description, or else consider the value-*o'fw in'a'formula such as as representing both individual constituents, in which n has a single definite value,'and also withtheun-derstanding that .n represents the averagevalue, based on completeness of reaction.

This may be illustrated as follows: Assume-that in any particular example, the molalratio of the propylene oxide to the sulfonate'is 15 to 1. Actually, one obtains products in Which It probably varies from 10'to20, perhaps even further. The average-value; however, is 1 5, assuming, as previously stated, that the reaction is complete. The product described by the formula may be described also in terms of method of manufacture, but insofar that a single hydroxyl only is involved, as differentiated from materials obtained by oxypropylation of polyhydric 'reactants, it appears moresatisfactory' to employ the'customary formula type description, as long'as the obvious limitations are completely understood.

'5 PART 2 For the purposeof'thepresent invention,,products.of the kind justdescribed,i. e., alcohol salts, are, ;in1 essence, intermediates which are esterifiecl with higher: fatty' acids or monocarboxy 'detergent forming acids.

It is well known that certain 'monocarboxy organic acids containing 8-. carbon atomsor more, :andgnot more than 56 carbon atoms, are characterized by the fact that they combine with alkali toproduce soapor soap-like materials. These detergent-forming acidstinclude .fatty acids, resin aci-ds, petroleum acids, etc. -For-tthersakewof convenience, these acids will be indicated by the formula R.COOH. Certain derivatives of detergent-forming acids'reaet'with alkalito produce soap or soap-like materials, and are" the "obvious equivalent of the unchanged or unmodified detergent-forming acids; for instance, .instead of fatty acids, "one 'mightemploy the. chlorinated fatty acids. Instead of the resin acids, one might employ the hydrogenated resin acids. Instead of naphthenic acids, one'mightemploy brominated naphthenic acids, etc.

The fatty acids are of the type-commonlyreferred. to as higher fattyacids; and, of course, this is.also true in regard to derivatives of the kind indicated, insofar that such derivativesyare 'obtained from higherxfatty acids. The petroleum acids include not only naturally-occurring naphthenic acids, but also acids obtained by'the oxidation of'wax, paraflin, etc. Such acidsmay have as .many as 32' carbon atoms. For'instance, see .U." S." Patent No. 2,242,837, datedMayflO, 1941, to Shields.

Although any of the high molal monocarboxy acids can be converted into esteramides of the kind described, by conventional procedure, it is my preference to employ hydroxylated esteramides derived from higher fatty acids, rather than petroleum acids, rosin acids, and the like. I have found that by far the most effective demulsifying agents are obtained from unsaturated fatty acids having 18 carbon atoms. Such unsaturated fatty acids include the higher fatty acids, such as oleic acid, ricinoleic acid, linoleic acid, linolenic acid, etc. One may employ mixed fatty acids, as, for example, the fatty acids obtained by hydrolysis of cottonseed oil, soyabean oil, corn oil, etc.

Particular reference is made to the use of naphthenic acids as esterifying agents becausev the product so obtained, or comparable products obtained from acids derived by the oxidation of petroleum, yield particularly valuable compounds for use in lubricating oils. I prefer to use the high molecular weight naphthenic acids, rather than those of lower molecular Weight. As is well known, the mixed acids can be divided roughly into three groups having the general formulae: CnH2nO2, CnHZn-ZO2, and CnH2n--402. The first group occurs largely in the lower boiling fraction of the mixture. They usually contain 6 or 7 carbon atoms and are colorless. The second group, usually the largest, contains acids of 8 to 12 carbon atoms having the structure:

H30 CH3 (CHQZOOOH The third group contains the heaviest molecules which are polycyclic and have from 12 to 23 carbon atoms. All

fractions from a carefully distilled naphthenic acid (24) contain some color, which, so far, has proved impossible to remove. Tarry residues account for the dark color of the crude, but these are largely removed by distillation. Since naphthenic acids are saturated and primarily cyclic, their soaps have much greater stability than thoseof other common liquid acids. The crude acid, as delivered, has a density of 8.04 to 8.44 pounds per gallon and a viscosity of 1.25 poises at 77 F. The acid values range from 160 to 270, but naphthenic acid used for soap manufacture usually has an acid value between 220 and 230. pH of the water extract is about 5.5 and the iodine value between 8 and 11.

The above description appears in substantially verbatim form in Industrial and Engineering Chemistry, volume 41, No. 10, October 1949, pp. 2080-2090.

Reference is made to particularly valuable commercial products of the type of naphthenic acids varying in acid number on an oil-free basis from 177 to 247, as ofiered for sale by the Oronite Chemical Company, San Francisco, California, under the grade designations of D, 6$H,5, L,, p.97

The higher fatty acid contains 18 to 22 carbon atoms in most instances. Some are available from various sources having a slightly larger number of carbon atoms. As has been pointed out previously, 20 to 23 carbon atoms is the upper limit for the readily available naphthenic acids. Resin acids, such as abietic acid, are also within approximate range. Another class of monocarboxy detergent-forming acids are the aryl fatty acids, and particularly arylstearic acids. See Industrial & Engineering Chemistry, volume 32, No. 8, page 1136, 1940. The cormnon aryl fatty acids, and more particularly, the arylstearic acids, include the following:

Phenyl stearic acid Tolylstearic acid Ethylphenylstearic acid Amylphenylstearic acid Xylylstearic acid Diethylphenylstearic acid Cymylstearic acid Cit! Diisopropylphenylstearic acid Pseudocumylstearic acid Tetrahydronaphthylstearic acid Chlorophenylstearic acid Ethoxyphenylstearic acid Phenoxyphenylstearic acid Xenylstearic acid 1 Any aryl fatty acids, and particularly aryl stearic acids, can be obtained from polycyclic aromatic compounds, such as naphthalene, and substituted naphthalene such as alkylated naphthalene. Common examples are monoalkylated naphthalene, in which the alkyl radical has 1 to 14 carbon atoms, or dialkylated naphthalene, such as dipropylated naphthalene, dibutylated naphthalene diamylated naphtalene, dinonylated naphthalene, or ditetraacylated naphthalene. Thus, monocarboxy detergent-forming acids are available in which there may be as many as 56 carbon atoms.

In light of the procedure employed to produce salts, it is generally preferable that the intermediate (alcohol salt) be the sodium salt, for the reason that usually the sodium salt is the most economical to prepare. If one subjects a phenol sulfonic acid of the kind described to oxypropylation, one probably obtains the propylated derivative at both the sulfonic acid position and the hydroxyl position, i. e., the final product is a complex glycol or diol. If one saponifies this product. in the presence of water and splits back the free acid, one then has a hydroxylated acid, i. e., a product having one hydroxyl and a sulfonic acid group. Such product can simply be mixed with a stoichiometric amount of the selected monocarboxy acid and heated to yield the ester acid. Since the product acts as its own catalyst, this particular reaction is comparatively simple. Compare with a similar reaction, as described in my co-pending application Serial No. 164,860, filedMay 27, 1950, now abandoned. I I However, such procedure involves the wastage of the propylene oxide, which is united with the sulfonic acid, except to the extent that it would be recoverable as a polypropyleneglycol. Previous reference has been made to the free sulfonic acid corresponding to the intermediate, to wit:

0 (CsHa0)n This product, of course, is identical with that described immediately preceding, with this difference; under the method of manufacture specified, all the propylene oxide esterifies rapidly, for the reason that the reactant per se is its own catalyst, i. e., is a sulfonic acid. The actual esterifications have been carried on in conventional appa: ratus; and on a laboratory scale I have used a glass resin pot, such as the kind described in U. S. Patent No. 2,499,365, dated March 7, 1950, to De Groote & Keiser. Furthermore, I have used both the gallon size autoclave and the 1% gallon size autoclave of the kind previously described. When the autoclave was used as an esterification vessel, of course, it was connected to the condenser, so that it could be used for refluxing or in combination with the phase separating trap. The reaction was. cont ducted until the amount of water evolved was equal to theoretical and until the reaction was completed, as indicated by some other test, such as the decrease in acid value, or decrease in hydroxyl value. After esterification, the product was neutralized by the addition of any of the usual basic materials, suchas caustic soda, caustic potash, ammonia, various ethanolamines, cyclohexyl: amine, amylamine, diamylamine, triamylamine, etc. My preference is to use enough xylene in addition to the two reactants so the mixture refluxes at about 150 C. The final product, with either the xylene present or xylene removed, was neutralized in the conventional manner. The finalproduct, on a xylene-containing basis, represented amber-colored, viscous liquids or sticky solids, or sticky semi-solids. For many purposes, the xylene may be permitted to stay in the final product. Needless to say, the

xylene could be replaced by any other convenient solvent that would not interfere with any reaction involved, such as cymene,.decalin, toluene, mesitylene, etc. The final product can, of course, be rendered solvent-free by distillation, and particularly vacuum distillation. product can be bleached by the use of various filtering chars, bleaching clays, or the like. The color is not objectionable for most technical purposes.

Purely by way of illustration, the following examples are included, although as has been pointed out previously, the particular esterification is exceedingly rapid and satisfactory.

Example A The alcoholacid intermediate of the structure O(CaHsO)..H

was obtained fromthe sulfonate described in Example 5, preceding. .In this sulfonate the substituent represented a molecular Weight of approximately 200. The phenol sulfonic acidradical sodium salt, exclusive of the substituent, represented another 200 molecular weight units and theifree acid, as differentiated from the sodium salt, represented a molecular weight of approximately 375. The oxypropylated ester acid obtained by reaction of 400 grams of the sulfonate with 1600 grams of propylene oxide following the procedure of Example 5, yielded an acid having a molecular weight, assuming complete com- The bination. of propylene oxide toolc p lace, of approximately 5.00 :grams, of-the above material, mixed with 200 grams, of xylene,.,were mixed with grams of commercialoleic acid and refluxed in a phaserseparatingtrap until approximately 8 cc. of water appeared in the trap. This was. in excess. of theoretical amount of water -but atthispoint the reaction mass still indicated the presence of unreacted carboxyl radicals, although compared to the original-value,it represented a small fraction of the initial oleicacid employed. The reaction was stopped atthis point, which represented a two-hour reaction period. An amount of alcoholic potash was addedjust sufficient to neutralizethe free sulfonic acid radical. The product, freedafromxyleneand alcohol, was-dark amber incolor and represented. a viscous liquid which was soluble in nonearomatic kerosene, and which showed comparatively minor hydrophile property. .-It ,was essentially hydrophobe in character, ,as indicated by solubility test, such as the kerosene solubility test. The product. was susceptible .to decolorization by bleaching with charcoal or filtering earth. However, as acouplingagent in emul-. sification or an additive in lubricants, decolorization was not necessarily required.

"Thesameyprocedure was employed, and the product neutralized .with caustic soda (20% solution). -After theaaddition of the caustic soda, refluxing :withxylene was continued-for a.short-.period to remove the water of solution. This sample was free from xylene by vacuum distillation. The properties of the sodium salt were substantially the same as the potassium salt. i I

A third salt was prepared, to wit, the triethanolamine salt. This particular salt showed slightly greater hydrophile character than the sodium or potassium salts previously noted. Obviously, oxyethylated triethanolamine, for instance, the product derived from one mole The same procedure was followed as in Example A, preceding, except that the 75 grams of oleic acid were replaced by anequal weight of naphthenic acid, approximate molecular weight 300, derived from California crude petroleum. The method of manufacture and the appearance of the final product weresubstantially the same as in Example A, when the corresponding salts were compared, i. e., sodium salts, potassium salts, and triethanolamine salt. In this instance another salt was prepared also by neutralization of cyclohexylamine. This salt had decidedly less hydrophile character and greater hydrophobe character than the corresponding sodium salt.

Example C The same procedure .wasfollowed as in Example A,

preceding, except that 75 grams of oleic acid were re Example D The same procedure was followed as in Example A, preceding, except that 75 grams of oleic acid .Iwe re replaced by grams of a monocarboxy acid derived by the oxidation of petroleum wax and having a molecular weight of approximately 400, and equivalent to about 26 carbon atoms. The method of manufacture ,and the appearance of thefinal product were substantially the same as in Example A, when the corresponding salts were compared, i. e.,sodiumsalts, potassium salts, and triethanolamine salts. This salt was prepared by neutralization of decylamine, and had decidedly..less hydrophile character and greater hydrophobeacharacter than the corresponding sodium salt. I

.Example E The same procedure was followed as imExamplesrA to E, inclusive, except that the sulfoniqacid, employemwas the one derived from the sulfonate ,described,in Example 9, preceding. In this instance, the molecular yveight of the sultonic acid was apparently somewhat, higher tl ian the sulfonic acid of Example 1, being ,approximately 400, as compared with 375. However, the molecular weight of the oxypropylated product was substantially the same as the same weights of reactants employed in all instances, i. e., 500 grams of the oxypropylated sulfonic acid and 75 grams of oleic acid, or the equivalent amounts indicated in Examples B to E, inclusive. No particular differences could be noted in comparing the analogous salts from this particular product with those derived from the sulfonic acid described in Example 5.

Attention has been directed to the fact that, although the solubility in kerosene is controlled in a large measure by (A) The length of the repetitious CzHsO chain and (B) By the presence and size of the acyl radical derived from the monocarboxy acid,

yet kerosene solubility obviously must be affected also by the size of the substituent in the phenolic nucleus and also by the particular cation which is combined with the sulfonic acid radical, and possibly, the position of the sulfonic acid radical in the nucleus, to say nothing of the overall size of the molecule as a whole. It is to be noted, however, it does represent a molecule of peculiar structure, in that there is present two distinct hydrophobe groups, i. e., the acyl radical, and also radical of the substituted phenolic nucleus. The sulfonic acid radical is more difficult to evaluate, except that it certainly tends in the direction of hydrophile properties, but here again is influenced as previously noted by the cation. There is also some difiiculty in appraising the solubility effect of the oxypropylene chain, for the reason that initially it may tend to introduce hydrophile efiects, which, when increased in sufiicient length, may give way to at least a modest and at times substantial hydrophobe effect. These points are emphasized simply to show the variety of structure and elasticity distribution of hydrophobe and hydrophile radicals which are possible in these compounds, which in any and all cases, must be soluble in nonaromatic kerosene.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. An ester salt of the following formula:

(CaHsOL- G S0;.cation in which R is selected from the class of hydrocarbon R sO sodium in which the occurrences of R, R and n have their previous significance and n has the identical value as previously, shall be soluble in non-aromatic kerosene; and with the further proviso that the corresponding unacylated sodium salt R SOLNB in which the occurrences of R and n have their previous significance and n has the identical value as previously, shall be insoluble in non-aromatic kerosene.

2. The ester salt of claim 1, wherein RCO is the acyl radical of a higher fatty acid.

3. The ester salt of claim 1, wherein RCO is the acyl radical of a naphthenic acid having approximately 20 carbon atoms.

4. The ester of salt of claim 1, wherein R'CO is the acyl radical of abietic acid.

5. The ester salt of claim 1, wherein RCO is the acyl radical of an acid obtained by the oxidation of paraffin and having about 26 carbon atoms.

6. The ester salt of claim 1, wherein R'CO is the acyl radical of a sulfoarylstearic acid derived from oleic acid and dinonylated naphthalene.

References Cited in the file of this patent UNITED STATES PATENTS 2,166,136 Flett July 18, 1939 2,184,935 Bruson Dec. 26, 1939 2,223,363 Flett Dec. 3, 1940 2,372,365 De Groote Mar. 27, 1945 OTHER REFERENCES Ser. No. 262,728, Guenther (A. P. C.), published June 15, 1943. 

1. AN ESTER SALT OF THE FOLLOWING FORMULA: 